Highly Diastereo- and Branched-Selective Rearrangement of Substituted N-Alloc-N-Allyl Ynamides via Pd-Auto-Tandem Catalysis

An auto-tandem catalytic, branched-selective rearrangement of substituted N-alloc-N-allyl ynamides was developed. This reaction provides ready access to complex quaternary nitrile products with vinylogous stereocenters in excellent diastereoselectivity, including the formation of contiguous all-carbon quaternary centers. The stereochemical outcome is determined via a Pd(0) catalyzed dipolar ketenimine aza-Claisen rearrangement inside a deep cleft on the catalyst. Computational studies exemplify the key role ligand geometry plays throughout the reaction coordinate in this previously unreported mechanism. This study provides new reaction pathways for both π-allyl and sigmatropic rearrangements.